Ben Wheatley's hilarious bloody tale takes place within the confines of a warehouse.

Once the guns start blazing in Ben Wheatley’s “Free Fire,” they don’t really stop. Prolific British director Ben Wheatley’s massively entertaining recovery from the messy J.G. Ballard adaptation “High-Rise” is a more controlled form of chaos, a chamber piece in which no chamber stays empty for long. Almost exclusively set in the confines of a small warehouse, Wheatley and screenwriter Amy Jump deliver the craziest movie shootout of all time by making an entire movie out of it. The cheeky dialogue and relentless violence leans heavily on the influences of Sam Peckinpah and “Reservoir Dogs,” although in this case the comic mayhem of the protracted battle amounts to little more than a lengthy gimmick. But a what fun gimmick: Less bullet ballet than bullet drum solo, Wheatley’s zany 90-minute set piece borrows the right ingredients to put on a good show.

Ever since his debut “Down Terrace,” Wheatley’s twisted stories take their time building up eccentric criminals before tossing in some violent twists. “Kill List” and “Sightseers” upped the ante — and the high concept “Free Fire” is no exception. Set in the late seventies against the backdrop of Northern Ireland’s guerrilla war, the movie takes a solid 30 minutes to establish its setup: Icy businesswoman Justine (Brie Larson, in a fierce alternative to her Oscar-winning “Room” performance) brokers an illegal gun trade between IRA soldiers Chris (a mustachioed and mostly forgettable Cillian Murphy) and Frank (Michael Smiley, one half of the hit man duo in “Kill List”) and scheming gun dealers Vernon (Sharlto Copley, relishing the role of a power-hungry lunatic) and Ord (a bearded Armie Hammer who’s the movie’s closest thing to a voice of reason).

In an ironic twist, just as the deal starts to come together in the contained setting, everything falls apart thanks to a pithy drama between two of the backup goons, the maniacal Harry (Jack Reynor) and obnoxious Stevo (Sam Riley). No amount of rushed diplomacy succeeds at containing their unrelated spat, and after one man drags his gun into the mess, they all follow suit. Everyone scrambles for cover as the real show begins.

The rest of “Free Fire” unfolds through echoing taunts and deafening shots, few of which hit their targets with much accuracy. The survivors stumble around behinds boxes and bullet-riddled cars, taking beatings until they can’t anymore; the body number climbs along with the symphonic cacophony of the gunfire. It’s not the most original shootout of all time, but it might be the craziest. Wheatley and Jump infuse the proceedings with an anarchic energy that provides no clear hero or the impression that any one character has the upper hand for long. That can make it hard to remain invested in the proceedings, and indeed, “Free Fire” reveals itself to be a bit of a one-trick pony once it hits the one-hour mark.

“Free Fire”

But Wheatley’s eager tone suggests that since he doesn’t take these characters too seriously, you shouldn’t, either. Covered in hokey wigs and glittery period-appropriate costumes that suggest someone raided the “American Hustle” cabinet, the gun-wielding survivors taunt each other as if they’re a group of elementary school kids engaged in trivial playground antics. “I’m getting away!” announces one ill-fated criminal as he attempts to do just that. When an interloper arrives at the scene with a sniper, another man accuses his foes of being “cheaters.” By the end of the show, however, nobody plays by the rules.

It’s one giant, unapologetic dose of bloody absurdity, and the talented cast is clearly having a blast with the mayhem. Larson’s businesslike demeanor once again proves her ability to command a scene with a single glare; the chameleonesque Copley, meanwhile, constructs a cartoon psychopath out of his darting eyes. Hammer’s more restrained performance only serves to provide some modicum of normalcy for the rest of the crazies to bounce off.

The conceit is so absurd it falls short of deepening the situation or creating much in the way of stakes surrounding anyone’s odds of survival. But Wheatley’s commitment to crowdpleasing antics makes it difficult to stop and consider the lack of depth. In a universe of shootout clichés, “Free Fire” manages to carve out its own niche, where the proverbial last man standing matters less than the journey to get him there.

Grade: B+

“Free Fire” premiered at the 2016 Toronto International Film Festival. A24 will release it in 2017.